I saw the movie today and I have to say its now my favorite of the trilogy. Everything was perfect. The great visuals, humor, storyline, the return of those two guards who argue with each other from the first movie (I missed them in Dead Man's Chest). I can see why people thought the storyline was confusing. It was in some cases but I felt it was easily overlooked.
As for a Fourth Movie I think its inevitable but if I were to write it only Jack would be back. This movie gave Elizabeth a little more of a point but honestly Will Turner always seemed well a filler character. Yes i know he had alot of points to play such as being the blood they needed in the first movie and all that but his character always seemed so unneeded and sorta boring. Even Elizabeth was sort of slow imo. I hope that Jack will get a new two main characters. Heck a solo adventure is fine with me. This film wrapped up this trilogy. Yet, as much as I want to see more let them take a few years off so we don't get too overfed with Captain Jack.